As shown in FIG. 1, in a computed tomography (CT) device, an X-ray source 101 and a detector module group 103 are installed on a rotatable gantry 104, The detector module group 103 is adapted to receive X-rays which are emitted from the X-ray source 101 and penetrates a scan chamber 102 in the CT device. Through rotation and movement of the rotatable gantry 104, CT scan of a patient in the scan chamber 102 is performed. The detector module group 103 includes a plurality of detector modules 1031 which are strongly connected. A side of each detector module 1031 which faces X-rays is installed with a detector which is adapted to receive X-rays. Another side of each detector module 1031 which is opposite to X-rays is installed with a plurality of analog signal output terminals and a plurality of analog-to-digital (A/D) chips. The plurality of analog signal output terminals are adapted to convert the received X-ray data into analog signals and output the analog signals. The plurality of A/D chips are connected with the plurality of analog signal output terminals through data lines. The plurality of A/D chips and the plurality of output terminals are installed on one circuit board and the number of the A/D chips is great, while the area of the circuit board is limited, thus, the density of electric components on the circuit board may be very high and pins' connection may be complicated, which greatly reduces the reliability of signal connection and transmission.